In the past decades, hundreds of articles have explored the mechanisms underlying priming. Most researchers assume that masked and unmasked priming are qualitatively different. For masked priming, the effects are often assumed to reflect savings in the encoding of the target stimulus, whereas for unmasked priming, it has been suggested that the effects reflect the familiarity of the prime-target compound cue. In contrast, other researchers have claimed that masked and unmasked priming reflect essentially the same core processes. In this article, we use the diffusion model (R. Ratcliff, 1978, A theory of memory retrieval, Psychological Review, Vol. 85, pp. 59-108) to account for the effects of masked and unmasked priming for identity and associatively related primes. The fits of the model led us to the following conclusion: Masked related primes give a head start to the processing of the target compared with unrelated primes, whereas unmasked priming affects primarily the quality of the lexical information.